The Trouble with Serums
by Don'tEvenBlink
Summary: SHIELD has been working on a deaging serum-without Nick Fury's permission. When the Avengers come in contact with the potion, Nick Fury finds himself dealing with the most powerful children ever created...Rated K , may change.
1. Chapter 1

**Hey guys. If one of you guys read my other stories, you know that I've given up on writing until summer's break, but I just watched the Avengers movie for the first time and I LOVED it. And I found myself rushing to the computer and the next thing I know, this one chapter has been written. So…here you go, I guess.**

Nick Fury was, well, furious.

And it was even more than usual. Apparently, some genius scientist had come up with the idea to make a _de-aging _serum, and someone, without notifying him, had given this guy the go-ahead. So, this guy—imagine the stupidity!—decided to test it out…while the Avengers were in there for a debriefing on their latest mission from an AI of their own. The scientist was crossing the meeting room, he tripped and fell, spilling the vial, and of course the contents of the serum owned properties of explosives, so it promptly blew up.

So now, Director Fury was heading into the other base's meeting room, unsure of what he would find. He hoped to god he wouldn't have to deal with a bunch of screaming babies…again.

Surprisingly enough, all of them looked ordinary enough. Tony was sitting impatiently as doctors surveyed him. "I'm fine," he insisted, pushing away the person who was trying to figure out his arc reactor. Natasha was talking to Clint, who looked slightly peeved as he sorted through his quiver, which was apparently damaged in the incident. Steve was sitting passively as another group of doctors checked him out, and Bruce was talking with some geneticists, trying to figure out what happened, while Thor was walking around the room aimlessly, Mjolnir swinging by his side, attached by a belt.

Nick sighed in relief, seeing the fairly normal scene, until one of the geneticists walked up. She was a quiet woman; he believed her name to be Patricia O'Donnell. She was sweet-looking, with rumpled blonde hair and nice, big blue eyes, which were now full of worry. "What's wrong, Ms. O'Donnell?" he asked, a little impatient. "It's Trish, and the problem is that they've…well, they've de-aged," she said, running a hand through her hair.

Nick glanced around the room again, surprised. The normalcy was almost overwhelming, he was so used to this. "I don't see anything different about any of them," he noted. Trish nodded. "We thought at first there was nothing wrong either, but Dr. Banner talked us into analyzing some hair fibers of him and the rest of the Avengers and through some advanced techniques he showed us, we determined that they're all at least three weeks younger than they should be. And some twenty minutes later, some of us returned to do further testing on the samples, and we realized it was even younger than before. Through some tracking we've discovered that the serum accelerates over time, so by the end of the week they should all be 17, and the end of next they'll all be about 6."

Nick sighed. He couldn't say he wasn't expecting something like this happening, but it was affecting the Avengers, which was very inconvenient. What would happen in those two weeks? Surely by the end of the second, they'll definitely be incapacitated. "Is there an antidote of some kind we can make?" he finally asked.

When Trish nodded, he sighed, this time in relief. "However, it won't be ready for three weeks, and we would have to check it before administering it to them." Fury groaned. Three weeks was too long for the Avengers to go MIA without the press wondering what was happening, not to mention Miss Potts, who was currently on vacation in California to see her parents, and Miss Foster, who still contacted Thor sometimes.

Then, he realized he had two perfectly capable geniuses at his disposal. "BANNER! STARK!" He yelled out, so suddenly that Trish jumped. Stark jumped off of the table, smirking at the doctors and Banner came over from his quiet discussion with the other scientists. "What's up, O great and wise one?" Tony asked, rolling his eyes at the serious look on the Director's face. "Yeah, what's wrong?" Banner asked.

"I need you two to help assist Trish and the rest of these people to come up with the antidote to you guys'…problem." Banner nodded, but Stark looked confused. "How do you expect me to help? I mean, I'm flattered and everything, but I don't actually know a lot about this kind of field." Fury gave him a look. "You literally became an expert on thermonuclear astrophysics overnight, when we alerted you about the Tesseract. I think you'll be fine. Go with Trish, here, and figure out all you can about the serum. I don't want to know how you were when you were six," Fury growled the last part, which made Tony even more amused, if possible.

"Okay, fair enough, but can I call my girlfriend first? I think she'd appreciate a heads-up so that when she comes back she won't try and kiss a six year old," he said jokingly, but there was a little bit of underlying fear in that. She'd almost skinned him alive when he forgot to call her after the battle of Manhattan (or as Tony called it 'The Epic Battle where The Stupid Horned-Dude lost to The Best Team ever Formed') and she'd said that she was thinking he was dead for the whole fifteen minutes it took for her to land. (A bit of an overreaction, in Tony's opinion, but he wasn't going to say that to Pepper's face.)

"Very well," Fury said, sighing. Every second counted, because he didn't really want to deal with pint-sized Avengers. That would be the scariest bunch of six year olds ever created.


	2. Chapter 2

**Hey again! This is more of a for-your-information chapter, so it's mainly focusing on why they're all going to be the same age, yada yada yada…Sorry, it's going to be kind of boring, but I'd recommend you read it in order to understand the rest of the story. Also, thanks for all the reviews! The only other time I've ever gotten a response to a single chapter like that was House of Talent. So thank you guys!**

For Trish, meeting the Avengers was like a dream come true. She'd always wanted to meet the team, even though she'd seen Clint and Natasha around, it was still the _novelty_ of them, of finally having someone stopping the super-villains in the world. Plus, Captain America was _hot._

Any other day, if she'd somehow managed to catch Bruce Banner she would've dragged him off somewhere and demanded a full lecture on his early research about the chromosome makeup and how it could possibly be used to cure cancer (**Sorry, just making up something that sounded science-y) **by injecting some type of immune system enhancer into the pairs **(God, I'm probably so wrong XD)**, but right now, she'd have to work so that she wouldn't have to deal with a six year old genius in two weeks.

Bruce powered into the lab, and rushed to where the hair fibers were being kept. He immediately cursed under his breath, taking a microscope and looking at it closer. "How much has it changed?" Trish asked, taking a seat next to him and peering over his shoulder, trying to find the differences that he'd seen with the naked eye.

"Apparently now I'm a month younger than I was an hour ago. This thing's accelerating, and faster than we expected," he said, swearing again. Trish noticed that a few of his grayish hairs that had lined his face were now the dark brown like the rest of them, noticed that he had a few less callouses on his hands.

"How much faster?" she asked, a little surprised. And at that stage, there were few things that would surprise her. "Instead of 17, we'll be at least 13, if not younger. We need to see if this has any type of pattern to it, and where the hell is Tony?" he tapped his fingernails annoyingly on the countertop, worried about what would happen by the end of the week.

Tony was being terrorized by his girlfriend.

First off, when Tony called she was in a board meeting that he was supposed to go to, so she was already annoyed before Tony called. When her ringtone blared, she picked it up without glancing at the caller ID; she already knew it was Tony. "What?" she snapped, totally not Pepper-like in any way.

Tony winced from the other side of the phone. "God, Pep, did you get coffee this morning? You sound pissed off." "Maybe that's because _someone_ just sent me on a plane yesterday to do a board meeting that _they _were supposed to go to," Pepper said from the other end.

"Wait…why are you calling anyway? Oh god, you didn't get into ANOTHER battle, did you? Are you hurt?" All of her annoyance was gone, replaced with worry. Tony was going to give her a heart attack one of these days…

"No, no, Peps, I'm fine…except for the fact that when you get back I _might _be three feet tall and have a fetish for Hot Wheels." Pepper paused for a second. "Okay, I give up. What's that supposed to mean?" "It means…well…" Tony quickly explained the situation using some not-very-nice words.

Pepper sighed, almost feeling like she should roll her eyes. Only Tony… "Right, well you'd better go and come up with an antidote, or else I'll make sure that you'll never get any cookies." Tony fake-pouted. "But when I was a kid I loved Oreos!" Pepper did roll her eyes at that one. "But seriously, go. I really don't want to be a PA for a six year old." Tony almost nodded, but then realized she couldn't see him. "Right, uh, bye." Pepper then heard the monotonous buzzing sound that told you someone had hung up.

Pepper smirked at her phone, before slipping it back into her purse. She wasn't worried, really. Sometimes she thought Tony Stark was still a child anyways.

Bruce was frantically writing equations on a white board when Tony returned. Trish was also writing stuff down into a notepad, nodding as Tony took a seat next to her. "So, what's up, Bruce? Are you trying to solve pi or something?" Bruce didn't even respond, just kept writing stuff down. Trish finally looked up and said, "He's trying to figure out the acceleration pattern of the de-aging serum."

Tony nodded. "How's that going for you, Bruce-y?" he asked. Bruce shook his head. "It makes no sense! All of the hair fibers are going at different rates, except for Natasha's and Clint's, and they're going at the same rate. But why isn't it working…? Ugh!" He threw the marker onto the floor in frustration. "Whoa, there, Bruce, we don't want the green rage monster tearing up the helicarrier, do we?" Tony asked slowly. Bruce groaned, and grabbed a chunk of his hair. "It makes no sense, though," he muttered.

Tony took a quick survey of the math equations Bruce had written on the board, all of them crossed out. "Hmm…did you try to graph one individually?" Tony asked, taking the marker and looking at his own data. He quickly figured out that it was going exponentially, and when he used Bruce's on the same graph, he saw that Bruce's curved a little steeper. "Hey, out of curiosity, how old are you?" Tony asked.

Bruce seemed taken aback. "Thirty-eight, why?" he asked, then immediately caught on. "How old are you?" he asked, coming to stand by Tony's graph. "Thirty-two," he said. "And if the Cap is about twenty-five, and both Natashalie and Clint are twenty-eight…bingo." He said. They all had different slopes, so that at some point they'd all catch up to be the same age. "So, the serum works by reversing your age to a certain point within a time frame!" Bruce said, catching on. "Yeah, and according to the graph we'll be thirteen at the end of the week, so…tomorrow I'll be at least three years younger. Hmm…" Tony muttered something under his breath that sounded like a curse about how Pepper would actually be older than him.

"Okay, but can we come up with a solution? I mean, as much fun as it would be to go through awkward stages of my teenage years, I'd rather not," Bruce pointed out. "You've been hanging around me too much," Tony mused, poking Trish with his Expo marker. She didn't even look up from her notes. "I mean, I pull off snarky like a boss, but when you try it its really weird. You're supposed to be the calm one," Tony continued.

"Yeah, but can we do it or not?" "I mean, really, you are supposed to _laugh _at my awesome sarcasm without supplying some," Tony said, ignoring Bruce's question. "TONY! I don't see any way we could come up with an antidote in the time frame, do you?" Bruce snapped. "Whoa, don't turn green! This stuff was supplied by _me, _so keep the rage monster controlled. And no, I don't see a way we can fix this. It seems like the thing will have to stop at some point, though, or else we'll end up fetuses in dead people's bodies. God, that would be gross." Tony shuddered at the mental image, but then turned inquisitive. "Although, that'd be a good science experiment…"

"Great," Bruce said, pinching the bridge of his nose. "Well, at least one of us won't change."


	3. Chapter 3

**Have I ever mentioned HOW MUCH I HATE MY COMPUTER?**

**I had a beautiful, spectacular 3****rd**** chapter ready for you, and I closed my computer for the night in order to actually sleep (something I don't get a lot of) and the next morning it installed window's updates, meaning all my work was LOST. And, even though I saved it, my computer decided to be stupid and not remember it.**

**I'm SO sorry it's taken this long to get a chapter up, and that it isn't half as beautiful and spectacular as my original manuscript. I swear I'm going to take my computer to the scrapyard after this. Stupid, pointless computer…Oh, and a week has passed, so they're all thirteen now.**

"ONCE UPON A TIME, A FEW MISTAKES AGO!" Tony suddenly started belting out as an upbeat song took over the loud radio Tony had in the living room of his Tower. "I WAS IN YOUR SIGHTS, YOU GOT ME ALONE!" Clint joined in. "YOU FOUND ME, YOU FOUND ME, YOU FOUND ME-E-E-E!" Tony started doing Gangnam style, which totally clashed with Taylor Swift's song. Clint joined in, and they locked arms and skipped around, screaming the lyrics as loud as they could.

"God, shut up!" Steve yelled over their obnoxious singing as he walked in, a newspaper under his arm. "NEVER, CAPTAIN KILLJOY!" Tony declared, still skipping around like a maniac. Steve groaned and sat down on the couch, the last bars of Taylor Swift filling the room and making his couch vibrate.

Tony flopped down on a parallel couch, sighing as a slightly less catchy song took over the radio. "JARVIS, turn off the radio," he commanded, and the radio was abruptly silenced, causing Steve to look bewilderedly around the room. He still hadn't gotten used to the AI that controlled all of Stark Tower.

Clint sighed too and immediately went off in search of snacks, leaving Tony and Steve in an awkward silence, the awkward intensified by the fact that Tony and Clint had just been yelling lyrics and dancing before Steve had come in.

Steve observed the man—well, boy really, that sat in front of him. Since they were all thirteen now, most of them looked a lot different than when he had first met them. For instance, Natasha's hair was now long, almost down all the way down her back, and was a dark, dark red, almost black; her eyes were also a lot greener and wider, for some reason.

Bruce looked a lot less worn and worried. His hair was a dark chocolate brown, and curlier. Locks of hair hung down into his deep eyes that were the same color, and his tea-colored skin was less wrinkled and calloused. He was unusually thin and slight, and usually dressed in whatever clothes managed to fit him now.

Clint, oddly enough, hadn't changed much. He was still incredibly skilled with the bow and arrow, and he was still built like he could tackle an alligator without being hurt. All that had really changed was that he had gotten shorter, he didn't have any stubble, and his hair was messier.

Thor kept his hair back in a ponytail now, and even as a…preteen (Steve wasn't actually sure how old Thor really was) he fit into Stark's clothes, which he was now using. Thor wasn't any shorter, just slightly younger looking, really. Steve was the same way, because apparently the serum was still working on him even as he de-aged.

Then there was Stark. Tony looked drastically different, without his goatee/mustache combination. Tony's windswept hair now covered most of his eyes, which were still as dark and mysterious yet carefree as always. Tony was slim now, but his body was edged with muscle, like a skateboarder's. His jaw was more pronounced than before, making him look like he perpetually had an attitude. He was at the moment wearing an MIT shirt that suspiciously fit, worn jeans, and red converse.

"Hey, Capsicle!" Tony waved his hand in front of Steve's face, effectively jerking the Captain out of his thoughts. "What?" Steve asked, vaguely annoyed. "I _said, _house arrest's dreadful and unnecessary, don't you agree?"

Steve sighed. Director Fury, in order to avoid confusion with the press, had ordered them under house arrest until everything was sorted. The restriction was actually meant for him and Thor, because Steve still followed military regimen and usually jogged around New York for an hour or so, and Thor found New York City to be 'profoundly bustling' and insisted on going sightseeing at least once a week; but of course Tony took it as a personal attack and was now nagging everyone to go outside, a rare sight since he usually had to be nagged to go outside his _workshop, _much less the tower.

"It is dreadful but necessary," Steve sighed, knowing fully where Stark was going with it. "Well, I've decided I'm going to leave the tower," Tony ignored Steve's comment. "Tony, we can't break perimeter!" Steve protested, knowing that once Tony set his mind to something, it would have to be done. Tony, however, was already standing up, almost donning a leather jacket before remembering that he wasn't half the size he used to be. "Don't think of it as breaking the perimeter so much as widening it," Tony winked, already heading towards the door. "Besides, I need some new shirts. These old college t-shirts won't last forever.

"College shirts?" Steve asked, confused. "Yeah, you didn't actually think that I went to college when I was eighteen, did you?" Tony smirked. "Oh, and JARVIS? Make sure that Steve can't contact SHIELD. Bye, Cap'n," Tony pretended to tip an imaginary hat at him before disappearing through the front door.

When Clint returned to the common room, this time holding a hoagie, Steve was glaring up at the ceiling like he wanted to murder it. "What's wrong with you?" he asked, throwing himself on Tony's favorite leather couch. "Can you go after Stark for me?" Steve asked suddenly, his authoritative voice taking over. Clint paused chewing for a moment, considered, and then swallowed. "Nah."

~TIME LAPSE OF TWO HOURS~

Tony was insanely bored. They say that New York City is amazing, that there is always something to do, somewhere to be. But no, if you're thirteen years old, apparently all people care about is where your parents are. Even when he went up to a street vendor to get a Snapple, the guy hadn't accepted money, saying that 'his parents needed to find their kid'.

Also, Tony had the distinct feeling that someone was following him. Whenever he turned around, there was always a man in a hood, staring at Tony as if Tony had turned into a gigantic green rage monster (which he hadn't—that was Bruce, not him). Tony had tried a bunch of maneuvers such as weaving through the slow-poke crowd, ducking into a women's lingerie store, and even stopping to talk to a hobo about the weather for fifteen minutes, but the man was always there.

Finally, he realized that wandering the streets weren't doing much good for entertainment. Griping to himself about a wasted hour, Tony meandered his way down the avenue, not quite ready to head back to the Avengers Tower, not wanting to face the wrath of Steve, Natasha, and Fury combined. For a thirteen year old, Natasha was absolutely lethal, especially if you're another thirteen year old.

But just as he made up his mind to head back, a hand grasped his shoulder and forced him to turn and face the person. It was the hooded guy, and upon closer inspection Tony realized he knew _exactly _who he was. Tony quickly masked his recognition, though, remembering that he had forgotten to call Rhodey about his…situation. Rhodey was going to _kill _him.

"Who are you?" he asked, employing the puppy dog look with finesse. Rhodey stared deeply into Tony's eyes, which he held steadily, keeping the confusion in his eyes. "Tony, what the hell happened?" Rhodey finally said. "Who's Tony? I'm Charlie…Charlie, uh, Chaplin," Tony stuttered **(get it? First one to pick up on that gets a shout-out!)**. "Charlie Chaplin? Seriously?" Rhodey raised his eyebrows doubtfully.

"Hey, my parents were creative with names! Now, strange man, if you'd just..." Tony tried to scoot around Rhodey, but Rhodey successfully blocked his maneuver with a muscled arm. "You know, this could count as child molesting," Tony tried weakly. Rhodey shook his head. "Tony, WHAT THE HELL HAPPENED?" Tony glanced around and realized that many people had stopped to stare at the pair, some even pointing to him and whispering. Tony sighed, knowing that some had been so shrewd as to guess that he was Tony Stark. Tony sighed through his nose, and grabbed Rhodey's arm, leading him into an abandoned alleyway.

When Tony thought they were deep enough into the narrow passage, he stopped and crossed his arms, leaning against the dirty brick wall behind him. "Seriously, Platypus? That could've gone better," he complained. "By tomorrow, half of New York will be speculating about the famed Colonel Rhodes yelling at a thirteen year old, and some of them crazy enough might guess the truth. Seriously, do you _know _how to keep a secret?"

Rhodey just stared. "Jamie? You there?" Tony snapped his fingers in Rhodey's face. He shook his head, and slapped away Stark's hand. "So…you're Tony?" he finally managed.

Tony rolled his eyes. "I think we've established that," he said slowly. "But…why are you thirteen? Do you still have your…glowy thingy?" Rhodey motioned towards his chest. "It's called an arc reactor, smart one, and yes, yes I do," Tony sighed. "Okay, explain just what the hell happened to you."

Tony groaned, but obeyed, explaining how some bozo scientist who didn't know what the crap he was doing created the serum, dropped it and it went KABOOM all over the Avengers, and now, sadly, he was de-aging.

Rhodey looked skeptical. "So how does that serum thing work?" "Uh, it's really hard to explain, let's just leave it at that," he suggested, knowing that Rhodey wouldn't understand the first thing about science. That was why he had gone to MIT; he was adept at science, but not even comparable to Tony. Rhodey just wasn't passionate about it.

"Okay…so…ah, this is awkward," Rhodey cussed under his breath. "Jeez, Platypus, I'm still my amazing, stunning self. What's so awkward about it?" "It's just, you look…like…like that," he gestured at Tony's face. "Hey! This face is still the handsomest you'll ever see!" Tony protested. Rhodey sighed. "At least your personality hasn't changed in the least. How about let's go to your tower and you can explain _again _what happened." Tony groaned all of a sudden, checking his watch. "Great, Mad-Eye's going to be there by now," he muttered.

"Mad-Eye?" "Oh, forgot to tell you that the Avenger team's taken over my tower now, and Fury had the brilliant idea to stick us all in there until we can't think straight and put us under house arrest, and I kind of broke the perimeter," he explained. "It's been two hours, so SHIELD should be finding out about it right about now."

"Two hours? Seriously, it takes them that long to figure out one person is missing?" Rhodey asked, surprised as they walked out of the alley and joined the masses of people. "Yeah, I'd upgrade their equipment for them, except I wouldn't be able to leave so easily if that happened," Tony shrugged. "Okay, well, I guess it's time to meet the Avengers." Rhodey tried to be nonchalant, but honestly inside, he was squealing like a fangirl.

**Yeah…sorry…but it's my computer's last wishes that you review!**

**~Don'tEvenBlink**


End file.
